一、豇豆白粉病豇豆白粉病在全国各地均有发生。主要为害叶片,也可为害茎蔓、叶柄和荚。叶片受害,先产生圆形白色小粉斑,后扩大,相互愈合,遍布全叶,沿叶脉扩展成粉带,色泽由白转为灰白至紫褐色。1.发病规律:病菌主要以闭囊壳或菌丝体随病残体越冬,翌年产生子囊孢子或分生孢子,靠气流传播,进行初侵染,后多次再侵染。一般干旱条件下或昼夜温差大、叶面易结露发病重。 First, the cowpea powdery mildew Powdery mildew occurred in all parts of the country. The main damage to the leaves, but also damage stems vine, petiole and pods. Leaf damage, the first round white small plaque, after the expansion, mutual healing, all over the leaves, along the veins expanded into a pink belt, the color from white to purple to purple brown. 1. The incidence of law: bacteria mainly closed shell or mycelium disease survived overwintering, the following year produce ascospores or conidia, by air flow, the initial infection, and then re-infection. Under normal conditions of drought or large temperature difference between day and night, leaf surface prone to condensation.